1. Field of the Invention
The present invention generally relates to an improved control for a regulated power supply, and more particularly to a control that electrically isolates the supply control from the power input.
2. Description of the Prior Art
Regulated power supplies are well known and widely used in the electronics and computer industries. One type of regulated power supply uses pulse-width-modulation to control the output voltage and maintain it at a level established by a reference. The power source is coupled to a modulating switch and the pulse-width-modulated output of the switch is coupled to the primary of a transformer whose secondary is coupled to the output. Among other functions, this power transformer provides electrical isolation between the power source and the output terminal.
Prior art power supply on-off controls are typically electrically connected to the primary side of the transformer. The on-off control may be a manually operated switch, or an electronically activated solid state switch or relay depending upon the application. As will be appreciated by those skilled in the art, if the on-off control is not electrically isolated from the power source, the control itself should provide isolation between the power source and the on-off control actuator. Providing such isolation in the on-off control can be costly and can add complexity to the system.